Name Date Class s7

Name Date Class

Introduction to Plants ■ Enrich

Desert Survival

You learned that all plants must have adaptations for obtaining and
retaining water. This is especially true of plants that live in the desert. To
obtain water, some desert plants have very deep root systems that can
absorb moisture far underground. Others have shallow, horizontal root
systems that can quickly absorb a large amount of water when it rains.

The aboveground surfaces of many desert plants are covered with
spines. These spines help to shade the plant from the sun and keep it from
getting too hot. They also help to reduce water loss from the plant by
shielding it from dry winds. Some plants in the desert have thick, fleshy
stems that can store water for long periods of time.

Many plants, such as the one shown below, survive dry periods by
becoming dormant or inactive. When a plant is dormant, it needs very little
water.

dormant

leaves

leaves and

flowers begin

to fall off

flowers

active

Answer the following questions on a separate sheet of paper.

1. What do you think causes the plant in the figure above to come out of
dormancy and become active?

2. Why do you think the plant loses its leaves and flowers when it becomes
dormant?

3. Do you think the plant shown above is more likely to have deep roots or
shallow horizontal roots? Explain.

4. A desert plant called the creosote bush has a double root system: It has
both shallow horizontal roots and deep vertical roots. Why would this
type of root system be an advantage to a desert plant?

5. Do you think a desert plant is more likely to have a thin cuticle or a thick
cuticle? Explain.